Description

Part I Unix Utilities/commands
The purpose of this lab exercise is for you to get some hands-on experience on using some fundamental Unix utilities (commands). After this lab, you are expected to be able to accomplish lots tasks using command line utilities, without resorting to your GUI based utilities such as File Manager. Command line execution is faster than GUI based utilities in general. Also in some systems GUI tools are not available at all and thus using command line utilities is your only option. We covered in class the following basic utilities/commands: man, pwd, ls, cd, mkdir, rmdir, cat, more, head, tail, cp, mv, rm, wc, chmod, chgrp, grep/egrep. We also discussed how to use pipe to use one
utility’s output as the input of another utilities. In the next class we will also cover uniq, sort, cmp/diff, cut, find etc.
You can get the details of each utility by using utility man. E.g., man chmod or even better, man 1 chmod
Go through the following 110 (small) practices. Write down your answers (with question #) besides the questions.
Note: Each question should be solved with only one entry of utility (e.g., cp file1 file2) or a pipeline of utilities (e.g., cat file1 | sort | wc).

0. Login to your home directory, and change to Bourne (again) shell by issuing sh or bash.The prompt should change from % to $. Now create a working directory for this lab, and navigate to the working directory.
2 ls xxx or ls
2. Check that the file is copied here.
$ ls xxx xxx $
4. Verify that the 2 files are copied successfully to the current directory.
$ ls xFile* xFile2 xFile3
$ ls xxx xFile2 xFile3
4 ls xFile2 xFile3 or ls xFile* or ls xFile?
5 mv xxx xFile1
5. Rename file xxx to xFile1
6. Verify that the renaming is successful.
One (professional) way to verify if an execution of a utility is successful is to examine the exit code (return value) of the executed process, which is stored in a system variable $?. Issue echo $? You should see 0, which means successful (this is opposite to C where 0 means false).
Also verify by listing files
6 ls xFile1 xFile2 xFile3 or ls xFile* or ls xFile?
$ your_command xFile1 xFile2 xFile3

11(2) echo $?
(2) Check the exit code of execution. You should get 1, which means unsuccessful (note that 1 means true in C).

12(2) echo $?

12. (1) Fix the problem in 11.
(2) Check the exit value of execution. You should get 0, which means successful
13. Move xFile1 into subdirectory lab7a (with same name)
14. Then move all the other 2 files (together) into lab7a (using one entry of utility)
drwx—— 2 yourname ugrad 4096 Jul 5 15:12 lab7a
Note that on each line, the first character – means this entry is a regular file, d means this entry is a directory.

total 12
-rwx—— 1 yourname ugrad 145 Mar 25 15:11 xFile1 -rwx—— 1 yourname ugrad 145 Mar 25 15:11 xFile2 -rwx—— 1 yourname ugrad 87 Mar 25 15:11 xFile3
2

(2) ls -l lab7a
$ ls -l lab7a total 12
-rwx—— 1 yourname ugrad 145 Mar 25 15:11 xFile1 -rwx—— 1 yourname ugrad 145 Mar 25 15:11 xFile2 -rwx—— 1 yourname ugrad 87 Mar 25 15:11 xFile3
17 ls -ld lab7a or ls -l -d lab7a
17. Then list the information of lab7a itself
$ your-command drwx—— 2 yourname ugrad 48 Mar 25 15:12 lab7a

18 cp –r lab7a lab7b
18. Copy directory lab7a to a new directory named lab7b (using one utility).
19. Verify that lab7b is created and the two directory are identical
$ ls -l * 19 ls -l *
lab7a: or ls lab7a lab7b
or ls lab7?
total 12 or ls lab7*
-rwx—— 1 yourname ugrad 145 Mar 25 23:32 xFile1 or ls lab7[ab]
-rwx—— 1 yourname ugrad 145 Mar 25 23:50 xFile2 -rwx—— 1 yourname ugrad 87 Mar 25 23:50 xFile3
lab7b: total 12
-rwx—— 1 yourname ugrad 145 Mar 25 23:32 xFile1
20 rmdir lab7a
-rwx—— 1 yourname ugrad 145 Mar 25 23:32 xFile2 rmdir: failed to remove
-rwx—— 1 yourname ugrad 87 Mar 25 23:32 xFile3 `lab7a/’: Directory not empty

20. Remove the whole directory lab7a using rmdir. What happened? 21 echo $?
21. Examine the exit code of the above execution, you should get 1, which means something wrong happened.
22 rm -r lab7a

22. Remove the whole directory lab7a using a more effective utility.
23. (1) Verify the exit code of above execution, you should get 0 now (2) Verify by trying to list lab7a

23(1) echo $?
23(2) ls lab7a or ls –l lab7a or ls –ld lab7a
$ ls lab7a ls: cannot access lab7a: No such file or directory
24. Move xFile1, which is in subdirectory lab7b, to current (parent) directory, using relative pathname.
25. Verify that the above move was successful. Instead of listing the files, let’s verify by searching for the files.
24 mv lab7b/xFile1 .
$ find . –name “xFile*” or find . –name “xFile?”

25 find . –name “xFile*” or find . –name “xFile?” 25 ” ” can be ‘ ‘
./lab7b/xFile2
./lab7b/xFile3
./xFile1
26 mv lab7b lab7working
26. Change the name of directory lab7b to lab7working
27 cd lab7working or cd ./lab7working
27. Navigate to directory lab7working 28. Verify that you are in lab7working
28 pwd
29 mv ../xFile1 .
$ your-command
29. Move xFile1 (which is in the parent directory) into the current directory using relative pathname.
30. Verify that the move was successful by listing all the files currently in lab7working
30 ls -l
$ ls -l total 12
-rwx—— 1 yourname ugrad 145 Mar 25 16:58 xFile1
31 more xFile1 or cat xFile1
-rwx—— 1 yourname ugrad 145 Mar 25 16:58 xFile2
-rwx—— 1 yourname ugrad 87 Mar 25 16:58 xFile3
32 more xFile1 xFile2 xFile3 or more xFile? or more xFile*
31. Display on stdout the contents of file xFile1
33 wc -l xFile1 or cat xFile1 | wc –l or more xFile1 | wc -l
32. Display on stdout the contents of the three files with one entry (Try more xFile1 xFile2 xFile3 or more xFile? Use space bar to proceed.)
33. Check how many lines xFile1 contains. You should get 5.
34 head -2 xFile1
34. Display (only) the first two line of xFile1
35 tail -3 xFile2
35. Display the last 3 lines of xFile2
code, you should get 0 36/37 cmp xFile1 xFile2 36/37 diff xFile1 xFile2
36. (1) Confirm that xFile1 and xFile2 are identical now, using a utility, which should return silently (Hint: cmp or diff). (2) Examine the exit
38 diff xFile2 xFile3
37. (1) Confirm that xFile1 and xFile2 are identical, using another utility, which should return silently (diff or cmp) . (2) Examine the exit code, you should get 0.
38. (1) Show that xFile2 and xFile3 are not identical, using diff utility, which will not be silent this time. Try to understand the message but don’t spend too much time on it. (2) Examine the exit code, you should get 1.
39. (1) Show that xFile2 and xFile3 are not identical, using cmp utility, which will not be silent this time. Try to understand the message but don’t spend too much time on it. (2) Examine the exit code, you should get 1.
FYI: these two utilities were used by some professors to do automated grading of your lab or labtest :
39 cmp xFile2 xFile3
gcc yourCode.c
a.out > yourOutputFile
cmp yourOutputFile professorsOutputFile
A student gets 0 if the last command does not return silently. That means, student gets 0 even if the student’s output contains an extra white space. 
40. (1) Concatenate the contents of the three files into a new file xFile123, in the order of xFile1,xFile2 and xFile3. Hint: use cat and redirection >.
(2) After that, show on stdout the content of xFile123.
40 (1) cat xFile1 xFile2 xFile3 > xFile3
(2) cat xFile3 or more xFile3 4
$ more xFile123
John Smith 1222 26 Apr 1956
Tony Jones 2152 20 Mar 1950 John Duncan 2 20 Jan 1966
Larry Jones 3223 20 Dec 1946 Lisa Sue 1222 4 Jul 1980
John Smith 1222 26 Apr 1956 Tony Jones 2152 20 Mar 1950
John Duncan 2 20 Jan 1966 Larry Jones 3223 20 Dec 1946
Lisa Sue 1222 4 Jul 1980 John Smith 1222 26 Apr 1956 John Duncan 2 20 Jan 1966 Larry Jones 3223 20 Dec 1946

41. Sort lines in file xFile123 so identical lines are adjacent now
41 sort xFile123 or cat xFile123 | sort or more xFile123 | sort
$ your_command
John Duncan 2 20 Jan 1966 John Duncan 2 20 Jan 1966
John Duncan 2 20 Jan 1966 John Smith 1222 26 Apr 1956
John Smith 1222 26 Apr 1956 John Smith 1222 26 Apr 1956
Larry Jones 3223 20 Dec 1946 Larry Jones 3223 20 Dec 1946
Larry Jones 3223 20 Dec 1946
Lisa Sue 1222 4 Jul 1980 Lisa Sue 1222 4 Jul 1980
Tony Jones 2152 20 Mar 1950
Tony Jones 2152 20 Mar 1950
42. Show on the stdout the content of xFile123, with duplicate lines removed/merged Hint: utility uniq will do the job
$ your_command
John Duncan 2 20 Jan 1966 42 sort xFile123 | uniq
or cat xFile123 | sort | uniq
John Smith 1222 26 Apr 1956
Larry Jones 3223 20 Dec 1946
Lisa Sue 1222 4 Jul 1980 43 sort xFile123 | uniq > xFile123compact or cat xFile123 | sort | uniq > xFile123compact Tony Jones 2152 20 Mar 1950
43. Remove the identical lines and save the result into a file xFile123compact. Hint: Just redirect the output of 42 using redirection >
44. Show on the stdout the content of xFile123compact. You should get same output as in question 42.
45. Issue chmod 775 xFile1, and then examine the resulting permission mode of the file. What do you get? You should get -rwxrwxr-x Can you understand what we are doing here?

44 cat xFile123compact or more xFile123compact

45 chmod 775 xFile1 ls -l xFile1 -rwxrwxr-x …

46 chmod 777 xFile1 ls -l xFile1 -rwxrwxrwx …
46. Now issue chmod 777 xFile1, and then examine the resulting permission mode of the file. What do you get?
You should get -rwxrwxrwx Can you understand what we are doing here?
47. Change the permission of xFile123compact using octal numbers so that the permission becomes
-rwxr–r– 1 yourname ugrad 140 Mar 25 17:23 xFile123compact
48. Change the permission of xFile123compact by giving group an execute permission. You should get the following result: -rwxr-xr– 1 yourname ugrad 145 Mar 25 17:23 xFile123compact
48 chmod g+x xFile123compact
49. Change the permission of xFile123compact by giving group a write permission, and remove read permission of the others of the file. You should issue chmod only once. You should get the following result:
49 chmod g+w,o-r xFile123compact
-rwxrwx— 1 yourname ugrad 145 Mar 25 17:23 xFile123compact
50. Change the permission of xFile123compact by removing write permission from group, and giving write and execute permission to others. You should issue chmod only once. You should get the following result:
50 chmod g -w,o+wx xFile123compact
–rwxr-x-wx 1 yourname ugrad 145 Mar 25 17:23 xFile123compact

47 chmod 744 xFile123compact
–rw-r—r– 1 yourname ugrad 145 Mar 25 31 17:23 xFile123compact

51 chmod a+w xFile123compact or chmod ugo+w xFile123compact or
chmod u+w,g+w, o+w xFile123compact
52 echo “this is a xxx new line” >> xFile1
52. Modify xFile1 by adding a new line at the end of the file. This can be done by echo “this is a xxx new line” >> xFile1 or cat >> xFile1 and then enter “this is a xxx new line”, followed by Ctrl-D.

Question 53-56 should be done without using sort. Utility ls can do sorting itself.
53 ls –l –t or ls -lt
53. List the files in the current directory, sorted by the modification time. xFile1 should be the first file in the list and other files are also sorted according to the modification time.
$ your_command total 20
-rwxrwxrwx 1 yourname ugrad 166 Mar 25 14:20 xFile1
-r-xr-x–x 1 yourname ugrad 145 Mar 25 14:12 xFile123compact
54 ls –l –t -r or ls -ltr
-rw-r–r– 1 yourname ugrad 377 Mar 25 14:11 xFile123 ……
54. List the files, sorted by the modification time, in reverse order. xFile1 should become the last file in the list.
55 ls –l –S or ls -lS
55. List the files, sorted by the size of the files. xFile123 should be the first file in the list and other files are also sorted according to the sizes.
$ your_command
total 20
-rw-r–r– 1 yourname ugrad 377 Jul 6 13:35 xFile123
-rwxrwxrwx 1 yourname ugrad 168 Jul 6 13:42 xFile1
-r-xr-x–x 1 yourname ugrad 145 Jul 6 13:37 xFile123compact
-rwx—— 1 yourname ugrad 145 Jul 6 13:27 xFile2
-rwx—— 1 yourname ugrad 87 Jul 6 13:27 xFile3
56 ls –l –S -r or ls -lSr
56. List the files, sorted by the size of the files, in reverse order.
57. Try to get the type of the file xFile123compact (Hint: use file utility)
xFile123compact: ASCII text 57 file xFile123compact
58. Try to get the type of one of your c source files.
hello.c: ASCII C program text 58 file hello.c
59. Try to get the type of one of your a.out files.
59 file a.out
a.out: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, …… not stripped

60 who | wc -l
60. Recall that utility who lists the people who are currently logged on to the EECS server. Get how many people are currently logged on to EECS server

61 who | sort

62 who | sort -k 3

61. Sort the list of people who are currently logged on.
63 who | sort -k 3 | head -3
63. Get the information of the first three people who logged on the system. Hint: pipe the result of 62 to utility head
64. Sort xFile123compact according to the numerical value of the 3rd field
64 sort -k 3 xFile123compact or cat xFile123compact | sort –k3
$ sort -k3 xFile123compact
John Smith 1222 26 Apr 1956
Lisa Sue 1222 4 Jul 1980
Tony Jones 2152 20 Mar 1950 cat can be replaced with more -3
John Duncan 2 20 Jan 1966 xFile123compact Larry Jones 3223 20 Dec 1946
65. The above result is incorrect (why?). Fix the problem by using the utility more effectively.
65 sort –n –k3 xFile123compact or cat xFile123compact | sort –n –k3
$ your-command
John Duncan 2 20 Jan 1966

John Smith 1222 26 Apr 1956
Lisa Sue 1222 4 Jul 1980 Tony Jones 2152 20 Mar 1950
Larry Jones 3223 20 Dec 1946
66. Sort xFile123compact according to the numerical value of the 3rd field, in reverse order
66 sort –n –k3 -r xFile123compact or cat xFile123compact | sort –n –k3 -r
Larry Jones 3223 20 Dec 1946 Tony Jones 2152 20 Mar 1950
Lisa Sue 1222 4 Jul 1980
John Smith 1222 26 Apr 1956
John Duncan 2 20 Jan 1966
67. [For your information] In the previous two exercises, John Smith and Lisa Sue, who have the same 3rd field value, did not get further sorted according to the 4th field. The following command sort xFile123compact according to the numerical value of the 3rd field, and then based on this, further sort according to the 4th field.
$ sort –n –k3 -k4 xFile123compact
John Duncan 2 20 Jan 1966
67 sort –n –k3 -k4 xFile123compact or cat xFile123compact | sort –n –k3 -k4
Lisa Sue 1222 4 Jul 1980
John Smith 1222 26 Apr 1956 Tony Jones 2152 20 Mar 1950
Larry Jones 3223 20 Dec 1946
68. Sort xFile123compact according to the year (the last field) cat can be replaced with more -3
xFile123compact
68 sort –n –k6 xFile123compact or cat xFile123compact | sort –n –k6
Larry Jones 3223 20 Dec 1946 Tony Jones 2152 20 Mar 1950
John Smith 1222 26 Apr 1956

John Duncan 2 20 Jan 1966
Lisa Sue 1222 4 Jul 1980
69. Sort xFile123compact according to the year (the last field), in reverse order.
Lisa Sue 1222 4 Jul 1980
John Duncan 2 20 Jan 1966
69 sort –n –k6 -r xFile123compact
John Smith 1222 26 Apr 1956 or cat xfile123compact | sort –nr –k6

Tony Jones 2152 20 Mar 1950
Larry Jones 3223 20 Dec 1946
70. Sort xFile123compact according to the 5th field (month)
$ sort -k 5 xFile123compact
John Smith 1222 26 Apr 1956
Larry Jones 3223 20 Dec 1946 70 sort –n –k5 xFile123compact or cat xfile123compact | sort –n –k6
John Duncan 2 20 Jan 1966

Lisa Sue 1222 4 Jul 1980 Tony Jones 2152 20 Mar 1950
71. In the previous question, month field is not sorted correctly (why?). Fix by using the utility more effectively.
$ your_command
John Duncan 2 20 Jan 1966
Tony Jones 2152 20 Mar 1950 71 sort –M –k5 xFile123compact or cat xfile123compact | sort –M –k5
John Smith 1222 26 Apr 1956

Lisa Sue 1222 4 Jul 1980
Larry Jones 3223 20 Dec 1946

72(1) who | grep yorku.ca
72(2) who | grep -v yorku.ca
The following exercises involve searching matches in files. Use egrep or grep –E (which guarantee to accept the extended regular expression) and make sure you are in sh or bash.
72. (1) Use grep or egrep to get the people who are currently logged on using yorku.ca network. (2) Then reverse the result, showing who logon using non yorku.ca network (so you can see clearly who is logon from the department and who is logon from outside, e.g., from home. Occasionally I use this trick to check if the professors I want to drop by is currently in the office – you’d better hold off going if he is currently logged on from non-York network such as bell or rogers 🙂
73. Display records of people in file xFile123compact who has a field value 2 in the record.
$ egrep 2 xFile123compact
John Duncan 2 20 Jan 1966
John Smith 1222 26 Apr 1956
74 egrep -w 2 xFile123compact
Larry Jones 3223 20 Dec 1946 Lisa Sue 1222 4 Jul 1980
Tony Jones 2152 20 Mar 1950
74. The above result is not desirable. Use the utility effectively so that only John Duncan 2 20 Jan 1966 is displayed. Hint: do a ‘whole word’ match.
75. Display the records of people in file xFile123compact who were born in 1950s. Hint: from the perspective of regular expression, a person’s year field is 195. where . represent any single character.
$ egrep
75 egrep 195.$ xFile123compact
John Smith 1222 26 Apr 1956
Tony Jones 2152 20 Mar 1950
76. Get the number of peoples in xFile123compact who were born in 1950s. You should get 2.
76 egrep 195.$ xFile123compact | wc -l
77. The EECS department maintains the records of all the students, staff and faculty members in a file
/etc/passwd, one person per line. Issue a command to see the content of the file. For such a long file, cat
77 more /etc/passwd
is not a good choice.
78 wc –l /etc/passwd or cat /etc/passwd | wc –l
78. Issue a utility to find out how many people are in the list. You should get about 3655.
79. Find out the number of people with name Wang in the file /etc/passwd. You should get about 43.

79 egrep -w Wang /etc/passwd | wc -l
or cat /etc/passwd | egrep -w Wang | wc -l
80. Get the number of students currently enrolled in the course. You should get 145. You can use the file directly (by giving the pathname), or, copy the file to your current directory.

81 egrep yourname classlist or cat classlist | egrep
81. Retrieve your record from the class list.
82. Get the number of students whose family name is yournameWang . You should get 0
82 egrep -w Wang classlist |wc -l or cat classlist | egrep -w Wang |wc -l
83. Get the number of students whose family name is Zhang. You should get 2.
83 egrep -w Zhang classlist | wc -l or cat classlist | egrep -w Zhang | wc -l
84. Confirm 83 by retrieving the record of students whose family name is Zhang. You should see two lines.
84 egrep -w Zhang classlist or cat classlist | egrep -w Zhang
85. Get the number of students whose family name is Leung. You should get 2.
85 egrep -w Leung classlist | wc -l or cat classlist | egrep -w Leung | wc -l
86. Confirm 85 by retrieving the record of students whose family name is Leung. You should see two lines.
86 egrep -w Leung classlist or cat classlist | egrep -w Leung
87. Get the number of students whose family name is Chen or Chan. You should get 2.
Hint, from the perspective of regular expression, Ch[ae]n or “Chan| Chen” will do the trick.
87 egrep Ch[ae]n classlist | wc –l or cat classlist | egrep Ch[ae]n | wc -l
88. Confirm 87 by retrieving the record of students whose family name is Chen or Chan. You should see two lines.
88 egrep Ch[ae]n classlist or cat classlist | egrep Ch[ae]n or egrep “Chan|Chen” classlist or cat classlist | egrep “Chan| Chen” classlist or egrep ‘Chan|Chen’ classlist or cat classlist | egrep ‘Chan| Chen’ classlist
89. Look for the students whose eecs login id (in the first column of the file) starts with cse.
$ egrep cse classlist
cse***** dshwet** ********* Dixit, Shweta cse***** pavi*** ********* Kugarajah, Pavithra cse***** pbst*** ********* Thabet, Pierre yuying cse**** ********* Yu, Ying

90. The above result is not desirable. Use this utility effectively, so the last line is filtered out.
90 egrep ^cse classlist
cse***** dshwet** ********* Dixit, Shweta cse***** pavi*** ********* Kugarajah, Pavithra cse***** pbst*** ********* Thabet, Pierre

91. cut is a utility that can extract columns of a text file. By default cut assumes that the columns are separated by tab. (We can also specify other delimiters such as space or comma). To specify the columns to extract, use -f.
Issue cut -f 1 classlist Observe that the only eecs user info (the first column) is displayed.
Issue cut -f 4 classlist Observe that the only names (the 4th column) is displayed.
Issue cut -f 1-3 classlist Observe that columns 1 to 3 are displayed.
Issue cut -f 1,4 classlist Observe that the first and the 4th column are displayed.

92 egrep the lyrics or cat lyrics | egrep the
92. Contains the
#So turn off the light, 1980
Say all your prayers and then,
Beautiful mermaids will swim through the sea, And you will be swimming there too. sea 1980 I got there by chance.
93 egrep -w the lyrics or cat lyrics | egrep -w the
93. contains the as a whole word
#So turn off the light, 1980
Beautiful mermaids will swim through the sea,
94 egrep [0-9] lyrics or cat lyrics | egrep [0-9]
94. contains digits
#So turn off the light, 1980
Oh you sleepy young 1970 heads dream of wonderful things, sea 1980 I got there by chance.
95. contains 1980
95 egrep 1980 lyrics or cat lyrics | egrep 1980
#So turn off the light, 1980 sea 1980 I got there by chance.
96 egrep 1980$ lyrics or cat lyrics | egrep 1980$
96. end with 1980
#So turn off the light, 1980
97 egrep sea lyrics or cat lyrics | egrep sea
97. contains sea
Beautiful mermaids will swim through the sea, sea 1980 I got there by chance.
98 egrep ^sea lyrics or cat lyrics | egrep ^sea
98. begins with sea
sea 1980 I got there by chance.
99. contains one (any) character followed by nd
99 egrep .nd lyrics or cat lyrics | egrep .nd
Say all your prayers and then,
Oh you sleepy young 1970 heads dream of wonderful things, And you will be swimming there too.
100. contains one (any) character followed by nd, but as a whole world only (so wonderful does not match)
100 egrep -w .nd lyrics or cat lyrics | egrep -w .nd
Say all your prayers and then,
And you will be swimming there too.
101 egrep ^.nd lyrics or cat lyrics | egrep ^.nd
101. begins with one (any) character followed by nd
And you will be swimming there too.
102. contains letter A or B or C or D
102 egrep [ABCD] lyrics or cat lyrics | egrep [ABCD]

or egrep [A-D] lyrics or cat lyrics | egrep [A-D]
Beautiful mermaids will swim through the sea, And you will be swimming there too.
103. begins with a capital letter
Well you know it’s your bedtime,
Say all your prayers and then,
103 egrep ^[A-Z] lyrics or cat lyrics | egrep ^[A-Z] 11
Oh you sleepy young 1970 heads dream of wonderful things,
104 egrep a.$ lyrics or cat lyrics | egrep a.$
Beautiful mermaids will swim through the sea, And you will be swimming there too.
104. ends with a and one other character.
105 egrep [abc]nd lyrics or cat lyrics | egrep [abc]nd

or egrep [a-c]nd lyrics or cat lyrics | egrep [a-c]nd
Beautiful mermaids will swim through the sea,
105. contains a character that is either a or b or c, followed by nd
Say all your prayers and then, 106. contains a character that is not a nor b nor c, followed by nd
Oh you sleepy young 1970 heads dream of wonderful things,
And you will be swimming there too. 106 egrep [^abc]nd lyrics or cat lyrics | egrep [^abc]nd

or egrep [^a-c]nd lyrics
107. Go back to the parent directory or cat lyrics | egrep [^a-c]nd

cd ..
108. Issue utility
108
find . -name “xFile?”
$ find . -name “xFile?”
What do you get? ./lab7working/xFile2
./lab7working/xFile1
109. Now issue the utility ./lab7working/xFile3
$
find . -name “xFile*”
109
$ find . -name “xFile*”
./lab7working/xFile123
./lab7working/xFile2
./lab7working/xFile123compact
./lab7working/xFile1
./lab7working/xFile3
$
What do you get?

110. Now issue
find . -name “xFile*” -exec mv {} {}.Lab7 ; What we intend to do here?
List directory lab7working and examine what happens to the files in lab7working?
109 Find all the files whose name begins with xFile, and change name of them.
Each new name now has a .Lab8 suffix.

Note: for solutions using egrep
• all egrep can be replaced with grep -E
• all the unquoted search patterns can be quoted
e.g., egrep the lyrics is same as egrep “the” lyrics or egrep ‘the’ lyrics egrep ^.nd lyrics is same as egrep “^.nd” lyrics or egrep ‘^.nd’ lyrics
Actually it is a good habit to always quote search patterns
Part II Common shell functionalities and corresponding meta-characters
In the last lecture we discussed some functionalities that are common among the different shells, and their associated meta-characters. In part I above we have experienced some of them, for example, Pipes |, Filename substitution (wildcards) * ? [], Redirections < > >>. Here you practice some more functionalities, including Command substitution ` `,
Variable substitution $, Conditional sequence && ||, and Quotes ” and ” “.
111. Filename substitution (Wild-cards * ? []). Navigate to working directory.
• Issue ls * Observe that all files in the directory are listed
• Issue ls xFile*.Lab7 Observe that all files whose name begins with xFile are listed
• Issue ls xFile?.Lab7 Observe that files xFile1.Lab7, xFile2.Lab7, xFile3.Lab7 (but not xFile123.Lab7 and xFile123compact.Lab7) are listed (why?)
• Issue ls xFile???.Lab7 Observe that only file xFile123.Lab7 is listed (why?)

112. Command substitution “
• Issue a single command to output There are 145 students in EECS2031Z where 145 comes from the result of a command that reads from file classlist.
• Issue a single command to output There are 2 students in EECS2031Z with family name Zhang where 2 comes from the result of a command that reads from file classlist.
• Issue a single command to output There are 3 students in EECS2031Z whose eecs username begins with cse where 3 comes from the result of a command that reads from file classlist.
112 you can also add double quote ” ” around the messages.
$ echo There are `wc -l classlist` students in EECS2031Z.

$ echo There are `egrep -w Zhang classlist | wc -l` students in EECS2031Z with family name Zhang

$ echo There are `egrep ^cse classlist | wc -l` students in EECS2031Z whose eecs username begins with cse.
113. Conditional sequence && ||. 1) For a series of commands separated by “&&” tokens, the next command is executed only if the previous command returns an exit code of 0, which means ’successful’. 2) For a series of commands separated by “||” tokens, the next command is executed only if the previous command returns a non-zero exit code, which means ‘unsuccessful’.
• Issue egrep -w Wang classlist and then echo $? to examine the exit code 1 which means unsuccessful (no matching found).
• Issue egrep -w Zhang classlist , and then echo $? to examine the exit code 0 which means matching found.
• Issue egrep -w Wang classlist && echo HELLO, observe that HELLO is not printed (why?).
• Issue egrep -w Zhang classlist && echo HELLO, observe that HELLO is printed (why?).
• Issue egrep -w Wang classlist || echo HELLO, observe that HELLO is printed (why?).
• Issue egrep -w Zhang classlist || echo HELLO, observe that HELLO is not printed (why?).
114. There are often times when you want to inhibit the shell’s filename-substitution (wild-card) * ? [], variablesubstitution $, and/or command-substitution ` ` mechanisms. The shell’s quoting system allows you to do just that. The way that it works is: 1) Single quotes (‘ ‘) inhibits both wildcard substitution, variable substitution, and command substitution. 2) Double quotes(” “) inhibits wildcard substitution only.

• Issue courseN=2031Z; (no space around =) This assign variable courseN with value 2031Z

Submission
If you decide to submit, write the question numbers and your answers for question 1-110, and 112 in a file, or, make a scan/image of your handwriting answers, and submit the file using submit 2031Z lab7 your_file_name